问如何将momentjs datetime转换为字符串，反之亦然

EN

datetime_from_moment = moment.utc().utcOffset('+0530')

datetime_from_moment_string = datetime_from_moment.toString()

Deprecation warning: value provided is not in a recognized RFC2822 or ISO format. moment construction falls back to js Date(), which is not reliable across all browsers and versions. Non RFC2822/ISO date formats are discouraged and will be removed in an upcoming major release. Please refer to http://momentjs.com/guides/#/warnings/js-date/ for more info.
Arguments:
[0] _isAMomentObject: true, _isUTC: false, _useUTC: false, _l: undefined, _i: Fri Mar 01 2019 22:10:42 GMT+0530, _f: undefined, _strict: undefined, _locale: [object Object]
Error
    at Function.createFromInputFallback (E:\workspace_javascript\testingProject\node_modules\moment\moment.js:320:98)
    at configFromString (E:\workspace_javascript\testingProject\node_modules\moment\moment.js:2368:15)
    at configFromInput (E:\workspace_javascript\testingProject\node_modules\moment\moment.js:2594:13)
    at prepareConfig (E:\workspace_javascript\testingProject\node_modules\moment\moment.js:2577:13)
    at createFromConfig (E:\workspace_javascript\testingProject\node_modules\moment\moment.js:2544:44)
    at createLocalOrUTC (E:\workspace_javascript\testingProject\node_modules\moment\moment.js:2631:16)
    at createLocal (E:\workspace_javascript\testingProject\node_modules\moment\moment.js:2635:16)
    at hooks (E:\workspace_javascript\testingProject\node_modules\moment\moment.js:12:29)
    at Object.<anonymous> (E:\workspace_javascript\testingProject\index.js:58:26)
    at Module._compile (internal/modules/cjs/loader.js:688:30)